Home solar update – to the roof!

Home solar installMy small experiment with solar started with one 100 watt, battery-connected panel resting on the ground in the backyard. I soon added a second and eventually a third panel. I learned a lot about every component, as well as the seasonal and weather-related variability of production.

Over the last few weeks, the hobby was turned over to the professionals, panels went up on the roof, and most of the system is now “grid-tied” instead of going to a battery. We now have 3,840 watts on the roof! Thanks to a very attractive financing option from Innovative Power Systems, our total costs should be similar or slightly lower than normal pre-solar electricity bills. The system should produce very close to the amount of electricity we use in an average year. We’re still waiting for the Xcel Energy engineer to sign-off on the install and switch on the grid-tied portion, but are told that will happen in days/weeks.

Of course, copious data will flow, as solar production AND total home usage will be monitored in real time. I look forward to trying to match usage to production curves.

I kept a piece of the system battery-tied for my hobbyist tendencies. The two smaller panels on the right connect to the battery charge controller and small battery bank in the basement. Both the panels and the batteries have been upgraded in size from the backyard setup, and of course the panels will no longer be shaded by the neighbor’s walnut tree. The usability of the battery system should be way up, and this should allow an interesting comparison between battery- and grid-tied systems.

Thoughts on Xcel’s 2030 Resource Plan

Xcel Energy, the state’s largest electric utility, has filed their 2016-2030 Resource Plan with the Public Utilities Commission. This begins a long process of commenting and modification until their plan is approved by that body (which can take years). The Resource Plan details what trends in usage Xcel expects, and what resources (like new power plants, etc) are needed to meet that demand. The plan is important because it identifies the infrastructure investments the utility will need to make, and also the resulting environmental performance, among many other details.

I’m slowly making my way through it, both for professional and personal interest, and hope to highlight some thoughts for you, my dozens of readers.

There are a lot of things to like in the plan, the first being that Xcel is planning to meet State greenhouse gas emissions reduction goals within their own system. This is unlike the previous plan, which showed emissions increasing between 2015 and 2030. The chart below, from Appendix D, compares the two plans. (State goals include a reduction of 15 percent by 2015, 30 percent by 2025 and 80 percent by 2050)

2030 CO2 Emissions Xcel

Most of the planned reductions in carbon pollution come from the addition of renewable energy resources to their system, as the chart below shows. By 2030, Xcel plans for 35 percent of their energy portfolio to be renewables.

Sources of CO2 reductions

However, I think the plan’s assumptions about the future cost of the solar portion of those renewables is probably too high.

Xcel plans to add over 1,800 MW of utility-scale solar to their system by 2030 (up from basically zero in 2015). This is a significant increase from the “reference case”, a ten-fold increase in fact. However, this slide was presented at a public meeting at the Public Utilities Commission:

Renewable Price ForecastXcel says this in Appendix J about their assumption:

As solar technology is still not fully mature, and costs are expected to decline and conversion efficiency to improve, it was assumed that the $95/MWh price holds throughout the study period. In effect, the assumption is that fundamental cost driver improvements will offset inflation.

So the rate of decrease in solar prices will match the inflation rate? Many sources have documented the dramatic decline in solar PV prices over recent years. Lazard seems to be an oft-cited source, and their 2014 Levelized Cost of Energy Analysis shows the price of energy from solar has dropped 78% since 2009. According to usinflationcalculator.com, the cumulative rate of inflation between 2009 and 2014 was about 10%. So, at least looking historically, this seems way off.

Of course, current precipitous declines probably won’t continue forever (most of the cost is now not modules). NREL says costs have been dropping on average 6 to 8 percent per year since 1998. If we assume just half of that decline per year (4 percent), solar energy would be around $51 per MWh in 2030. Using some very back-of-envelope calculations, a price difference of $46 per MWh in 2030 means costs for new solar energy shown in the Plan’s “Preferred Plan” scenario could be over-estimated by $97 million.

This is significant not just because the price estimates of the Preferred Plan may be too high. In preparing the plan, Xcel also ran seemingly dozens of other scenarios, some including CO2 reductions of over 50% in 2030 (compared with 2005). The price difference, according to Xcel, between the Preferred Plan scenario and the scenario with the largest CO2 benefit is $172 million (from Appendix J). These other scenarios which seem too costly may actually be more in line with what Xcel is currently asking to spend once dropping technology costs are factored in.

Transit priorities

I have mixed feelings about streetcars. But if we’re going to pick on them, let’s do it for the right reasons, like the fact that they don’t have dedicated right of way.  Yesterday the Pioneer Press reported that the Met Council was presented with a report about streetcars that “questions whether the costs outweigh the gains”.

Dollars are one way to measure cost, and if we’re spending too much to get gains, that is bad. How much money do we spend on transit elsewhere to get gains?

The proposed Nicollet streetcar in Minneapolis will cost $200 million and serve 9,200 riders in 2030. Bus Rapid Transit proposed for the Gateway Corridor will cost $469 million and serve 9,300 riders in 2030.  That’s double the cost per rider.  The Met Council has already adopted its Transportation Policy Plan, which includes the build-out of Gateway in the “Current Revenue Scenario” (meaning they don’t need any new money from the legislature or others). Bottineau and Southwest LRT also come in with price tags significantly higher per rider than the Minneapolis streetcar (Southwest is more than double).

Yes, we could be choosing arterial bus improvements on Nicollet instead of streetcars. That might be good.  But we could also be prioritizing expenditures across our regional transit system – looking at projects that have the highest cost-effectiveness per rider, or that most effectively address current inequities in job or destination access.

If we were really serious about costs and benefits, we’d be building projects like Hennepin Avenue Bus Rapid Transit tomorrow, which has a cost per rider 55 times lower than Gateway Corridor.  Instead, it’s on the “Increased Revenue Scenario” list, waiting in the breadline with the other high-value bus improvement projects, for the legislature to maybe, someday, hopefully fund.

Raising Florida

Miami Beach is starting to raise roadways to keep seawater off them:

In an area that has seen its fair share of roadwork during the past few years, city officials want to raise West Avenue between 1½ to 2 feet during the next few years in an effort to prepare one of the lowest-lying points of Miami Beach for anticipated sea level rise.

Raising the road would be tied to stormwater drainage and sewer improvements that include installing more pumps to prevent flooding from rain and high tides. The first phase, which will likely begin in February, involves work on West Avenue from Fifth to Eighth streets and from Lincoln Road to 17th Street. This phase would last until August.

The West Avenue Neighborhood Association met Wednesday night with city officials to discuss the plans. Public Works director Eric Carpenter told the packed room of about 100 residents — some skeptical and some more in favor of the plan — that he prefers dovetailing the street raising with the underground infrastructure work rather than tearing up the street several times.

“It doesn’t really make any sense to disturb those segments of the street twice,” he said. “We’re moving forward with the stormwater improvements. What we’re trying to do now is get a consensus from the community that we want to move forward with everything else on that street so that we don’t have to come back later and tear it up again.”

With a higher road, the city would create transitions from the road to the sidewalk that include, depending on the property, a higher sidewalk, steps down to the sidewalk and/or extra drainage components to ensure that no water from the street is draining onto private property.

The first phase of the project will cost $15 million.  A few reflections on this:

  • What about the buildings?
  • Local government officials would have a much steeper political hill to climb to spend $15  million on climate mitigation (emissions reduction) work.
  • I predict the costs of (attempting to) adapt to climate change will mostly be borne locally, be largely uncounted at the macro scale (and thus make mitigation seem expensive in comparison), and will often turn out to be a waste of money (since they won’t work for very long). I hope I’m wrong.

Land of 9,999 Lakes

The final version of the Met Council’s “Feasibility Assessment of Approaches to Water Sustainability in the Northeast Metro” has been released.  I posted my thoughts about this study before, but here are more rantings mostly pulled from my twitter feed.

The study says conservation of water is probably cheaper, but that’s not in this study, and we’ll get to it later (date 2015 TBD). From the study:

The alternatives evaluated should be viewed as examples. The best option for moving forward may be a hybrid of the examples considered in this study, and could involve approaches that were not considered in this study. For example, communities in the northeast metro could utilize less expensive approaches. These might include conservation or stormwater reuse to reduce groundwater pumping before making large-scale investments in alternative infrastructure solutions. Such a plan could couple these less expensive options with aggressive monitoring of groundwater and surface water, and set triggers for further action in the event these less expensive approaches are not effective.

So, we didn’t analyze the best and cheapest options, but we went ahead and did some demand forecasting so we could size some pipes anyway.

Households in many of the communities in the study area pay less for potable water each year than a family might pay towards their smart phone bill each month.

Water rates, from page 6 of the study

Water rates, from page 6 of the study

My household only has two smartphones, and we pay about $140 per month.  Add a few teens to the mix, and you get the point.  Water this cheap is obviously a triumph of civil engineering (and socialized infrastructure costs), but will likely make meaningful attempts at conservation difficult.

The study expects water consumption to grow 56% by 2040 while population will grow 37%.  Historically, population growth in Minnesota has outstripped increases in (permitted) water use.  From 1988 to 2011, population in the state grew about 24% while water use increased only 12%. Like electric utilities, water utilities nationally are also struggling with declining sales. The Met Council study doesn’t present any data on water usage trends in the study area communities (that I found).  I’m not sure why they are projecting this large increase in water use per capita (perhaps they are planning for many more golf courses?).  If any enterprising reader wants to dig in to the DNR data, trends for the counties included in the study area could be produced.

Searching the study for the words “grass” or “lawn” yields zero results.  As I mentioned in the previous post, the study doesn’t really attempt to analyze what the end use of water is in the study area, although looking at the “peak usage ratio” hints that a lot of it is landscape-related.

For just the operating costs of each alternative infrastructure solution (not including capital costs), you could pay each household $30 to $422 each year to use less. Annual operating costs of the alternatives vary from $1.3 million to $20 million.  The study area will include 189,470 people in 2040.

In other parts of the country with water supply issues, homeowners are paid to turn turf grass into water-efficient landscaping.  In the California Bay Area, homeowners can get a rebate of $1 per square foot for lawn removal.

For the some capital cost as the medium-priced option in the study, homeowners could be paid to remove 6 square miles of grass at a rebate cost of $1 per square foot. Plus they could be paid to remove 129 football fields-worth (7.5 million square feet) in every future year for the equivalent operating costs of that option.

Photo: Sprinkler, Creative Commons licensed by flickr user Shaylor

November solar doldrums

cloud gif

I made this gif of visible satellite imagery from the NOAA’s Geostationary Satellite Image Archives. It basically shows cloud cover over the last 12 days at about 1 pm (19:15 zulu) each afternoon. This is a high-tech way of saying we’ve barely seen the sun for the last two weeks.

The implications for my 300 watt off-grid solar project are that almost nothing is being produced, and I’m not running anything from the batteries. With no sun in the forecast, I’m concerned about them sitting at a low stage of charge for days (or weeks at this point), which can reduce the life of lead-acid batteries.

In Minnesota in the winter, solar needs a backup, or at least a supplement. It’s great to have a grid. If I were truly off-grid, I would need some other kind of backup unless I was willing to significantly overbuild batteries or panels.

Creating a low-carbon transportation system for MSP: Part One, Baselining

My latest at streets.mn does the carbon accounting which should have been part of the Draft 2040 Transportation Policy Plan developed by the Met Council.

Thrive MSP 2040, the new regional plan for the 7-county metro adopted by the Metropolitan Council, includes moderately strong language about addressing climate change.  But the main implementation tool we’ve seen so far from the Council, the Draft 2040 Transportation Policy Plan, doesn’t go nearly far enough.  In fact, it doesn’t even start where it should, with a baseline of emissions.

In this and future posts, I’ll try to do what I think the Draft Transportation Policy Plan should have done – identify where we’re starting from and where we need to go in terms of transportation-related greenhouse gas emissions.

It’s got charts, so you’ll want to read the rest.

My comments on the Draft Transportation Policy Plan

CurrentRevenueThe Metropolitan Council held a public hearing tonight on their draft Transportation Policy Plan. If you care about transit or transportation issues in the region, you should comment (you can do so through October 1). Here are four comments I have on the plan:

  1. Our urban areas are significantly underserved by this plan. Even under the “increased revenue scenario”, we will spend $5 on transit to serve suburban commuters for every $1 we spend on transit improvements to places where transit makes economic sense (see here for my attempt at a geographic breakdown of projects). The Met Council, in the Thrive 2040 plan, has said they want to match transit service to the number of riders and intensity of land use. This plan does not do that.
  2. The plan currently prioritizes projects like Gateway BRT (9,000 riders at $50,000 per rider) over projects like Hennepin Ave BRT (23,000 riders at $896 per rider). This is an example of how our urban areas (that are expected to grow significantly) are underrepresented in this plan.
  3. The Transportation Policy Plan, as an implementation plan of Thrive 2040, should identify how our transportation system will be planned to reduce greenhouse gas emissions (another goal of Thrive). While the plan mentions “reducing vehicle trips”, there is no analysis in the plan of whether the scenarios presented will increase or decrease emissions from our regional transportation system. We can’t wait another 10 years for the next update of the regional plan to take significant action on climate change.
  4. It’s definitely not all bad. The Met Council for the first time has identified regional priorities for a bicycle network, which will give communities the ability to apply for funds to upgrade their local network if it matches the regional plan. Many of the transit projects identified are much needed improvements (Hennepin, Chicago, West Broadway), but are simply not adequately prioritized.

Questions about the northeast water supply plan

Over at streets.mn, I ask some questions about the Met Council’s new northeast metro water supply plan.  Here is a big one:

Where is the conservation alternative?  The cost and feasibility of  reducing water use are not analyzed as part of the report.  Building nothing and simply asking/incentivizing/requiring people to use less may be the cheapest option.  According to the report, water use in 2010 was 92 gallons per person, per day in these communities. The ratio of peak day demand to average day demand ranges from 1.7:1 in Forest Lake to 5.9:1 in Lexington.  The report hints that this is “mainly attributed to irrigation and outdoor water use needs”.  Sprinkling lawns in other words.  Many options exist for conserving (potable) water – from retrofitting toilets, sinks and showers, to using captured rainwater to irrigate, to simply paying people to remove lawns and replacing them with low-water alternatives.  For the cost of the alternatives to serve all northeast communities with new water supply (~$600 million), you could pay every household over $1,400 to remove lawn, and keep paying them $40 every year after that.  Without an analysis of conservation alternatives, this report seems inadequate.

Read on.