Wednesday, November 2, 2011

My Solar Energy Investment

A letter in the current Harvard Magazine, by an astronomer at UCLA, prompts me to blog about my photovoltaics. Professor Jura has described his experience here.

I live in an old house in Brookline, perhaps half a mile from the Brigham and Women's hospital. One day I noticed that, in spite of the houses around us, the flat roof on the garage has a pretty clear southern exposure. After getting in a contractor and running some financial models, I determined that a PV installation would pay for itself in about 7 years. It went online in May, and so far the energy production is a little ahead of the projections. Generates 5 kW peak and should produce about 7 MWh/year. The financial model has three components: tax credits for part of the capital investment; reduced electric bills because I pay only for net usage; and income from sale of State Renewable Energy Credits, one per MWh I generate independent of my electric usage.

System is depicted below. It is all but invisible from the street. And you can look here to see its production, either power or energy, by either day, week, or month. PV panel prices have softened in the past year so I'll bet it would have a shorter payoff period if I were starting today. Glad to answer any questions offline.


  1. Hi there! great stuff, glad to drop by your page and found these very interesting and informative. Thanks for sharing about solar energy tax credits, keep it up!
    Despite this growing demand and support for renewable energy, a fragile economy, volatile commodity pricing, and the lack of national energy policy have combined to pave a challenging road for renewable energy advocates and stakeholders. Economies of scale and new manufacturing processes are making alternative energy production more competitive, but until it achieves parity through innovation or regulatory policy, the success of green energy companies may largely depend on their ability to optimize Green Energy and Cleantech tax incentives to attract investors and maintain sustainable balance sheets.

  2. Solar power is both environmentally and user friendly. The solar energy does not use fuel to produce energy and also does not let go any harmful pollutants into the environment.
    solar power in Nigeria.

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  6. Benjamin Franklin got it wrong when he said "A penny saved is a penny earned"-- The penny saved is after-tax but the penny earned is subject to tax.