Researching Solar Power for Wisconsin

With energy prices at or near record highs (oil was over $100 per barrel today), we've started considering the possibility of installing some sort of solar system on the house to defray the rising energy costs. However, this is not a simple decision. First of all, it takes significant up-front-investment ($10-$50k it looks like), and there are many different types of systems and options to consider. Plus, there's a host of tax credits and incentives to consider. Then there are zoning issues and restrictive covenants to take into consideration.

I'll try to break down our research in a few blog postings. They will be written as I work my way through the various web sites and find out information.

First, we have a restrictive covenant that would seem to doom the project from the beginning. Renewable energy systems are not allowed in our neighborhood. However, we can appeal to an architectural review committee to be allowed to 'break the rules'. I'm confident that a system that is mounted flush with the roof would be OK. our house's south-facing roof-line faces away from the road, and is quite tall relative to other neighbors, so it should be possible to install a system that is fairly unobtrusive.

So, what type of system are we looking for? We would like a system that

• has a pay-back period of five years or less,
• connects to the grid with net metering,
• can handle 90% of our annual electricity needs (10 kWh),
  
• can be installed fairly flush with the roof,
  
• is relatively maintenance-free, and
  
• works in Wisconsin winters.

We've ruled out wind systems, because we're in a fairly residential neighborhood, and don't see a wind turbine passing muster with either the neighbors or the architectural review committee.

One of the first steps in setting up a system is to assess the site. In Wisconsin, there are certified site assessors charging between $200 and $500 for a full assessment (Focus on Energy will cover 60%, so our cost would be $80-$200). For solar systems, you need a south-facing location with unobstructed view of the sun for as long as possible each day. Fortunately, we have a roof that faces almost directly south, and is high enough that there are very few obstructions once the sun is up. It also seems that Wisconsin gets enough sun - although November/December can be dreary, the highest-demand days are in the summer.

Most of the rest of this is focused on photovoltaics.

Funding Incentives

• Focus on Energy: 25% of construction cost up to $35,000 (program expired 12/31/07 - perhaps a new one coming up?)
• Update 1/3/08: Program will continue with the same amounts at least through end of 2008. New forms will be up on web site within a week.
  
• Federal tax credit: 30% of construction cost up to $2,000 (extended to 12/31/08)
• Net metering - sell any excess energy to the utility. This means all energy is used - no loss to storage in batteries. More sun - better economics.
  

Sizing of System

• Current energy consumption: ~11 kWh /year
• System need: ~7.5 kW panels (6-800 square ft)
• Approximately 4 daily hours of sunshine in Wisconsin (1,460 hours per year).
• A 7.5 kWh system will thus generate 10,950 kWh per year
  
• Price range: $40,000 - $50,000 (plus installation - it seems possible to most of it as DIY)
  
• $45,000 after FoE and IRS incentives: $31,750
  
• One year cost of electricity: ~$1,400

Hmm, a loan of $31,750 would have to be mortgaged over 30 years at 2.3% interest in order for the electricity savings to cover the cost. This doesn't take into account any rises in energy cost (or consumption), or possible tax benefits/disadvantages of increasing the value of the home.

Perhaps an investment of this magnitude to save the environment is better made in carbon credits? Or maybe more research needed...