05.12.18
Why California’s Proposed Mandate for Roof-top Solar Makes No Sense
The California Energy Commission is proposing changes to building codes that would require the installation of roof-top solar panels on all new buildings starting in 2020.
Here are the top 5 reasons that mandating roof-top solar for new residential construction in California makes no sense whatsoever:
1) Roof-top solar installations are much more complex and expensive than utility scale solar installations. Far more time is spent getting set up, rigging safety harnesses and moving racks and solar panels up to the roof than is spent actually mounting the solar panels. Electrical connections are also significantly more expensive requiring inverters at each home.
2) Roof-top solar installations are far less effective than utility scale solar installations. The roof pitch and north-south orientation of a roof is never ideal in terms of collecting the most solar energy. Houses are often surrounded by trees, hills, or high buildings which further reduces the solar energy captured especially in the morning and late afternoon. Utility scale solar panels are usually mounted on racks which move to follow the path of the sun resulting in much greater capture of available solar energy.
3) When solar panels are installed on a house the local electrical utility has to upgrade the equipment in the neighbourhood in order to handle the bi-directional flow of electricity in a system that was designed to distribute electricity, not collect it. Because the residents with the solar panels are actually spending less for electricity (and often actually collect money from the utility for electricity generated by the solar panels) the cost of these upgrades must be born by people that have no ability to install solar panels: renters, those living in apartment buildings, and those on fixed or low incomes.
4) The average life of a roof in California is about 20 years. That means that the entire installation of solar panels will have to be removed and replaced as part of the roof replacement. Solar panels do lose efficiency over time so that it would probably make sense in most cases to simply redo the entire installation which will be even more expensive than the initial installation because of the need to remove and dispose of the old panels.
5) California already has a lot of solar energy developed to the point where the excess generation at mid-day is becoming a problem. The only solution to that problem, and therefore the only way to make effective use of further development of solar energy, is the implementation of large scale energy storage systems. Whether that energy storage is through the use of batteries, pumped hydro storage, molten salt, or some technology that has not yet been commercialized, storage at individual homes will be dramatically less efficient and more costly than centralized energy storage.
Geoexchange – a Far Better Alternative to Address Climate Change Concerns
There is an alternative that would provide far more benefit in terms of reducing energy demand for the entire life of a building and which would address climate change concerns far more effectively. That technology, already in widespread use, is termed geoexchange (implemented using geothermal heat pumps).
Geoexchange uses the constant temperature of the ground at depth to provide both heating and cooling of a building using approximately half the energy required by traditional heating and air conditioning systems. The cost of installing a geothermal heat pump would be a fraction of the cost of installing solar panels and geothermal heat pumps cut electricity demand in the late afternoon and evening – the peak demand times when California is still dependent upon fossil fuels and nuclear to provide power for lighting and air conditioning.
In cooling mode geoexchange takes advantage of the fact that the earth at depths of 50ft is much cooler than the air temperature.
In heating mode geoexchange takes advantage of the fact that the earth at depths of 50ft is much warmer than the air temperature. One of the most widespread ways to heat buildings is through the burning of natural gas in traditional furnaces. Natural gas is a fossil fuel and heating buildings using that energy source emits enormous amounts of carbon dioxide. Geoexchange, on the other hand, uses the earth as a heat source and heat sink to heat and cool buildings with no combustion of fossil fuels and no carbon dioxide emissions.
Geoexchange systems are integrated internally within the building so they do not have to be touched when roofs are replaced or other renovations to a building take place.
Reducing the energy requirements of a building using geoexchange, better insulation, and a host of other net-zero technologies is a much better approach than generating additional solar energy at mid-day which has to be stored or curtailed because there is no demand for it at the time it is generated. If California law-makers are serious about addressing climate change concerns, requiring geoexchange for all new buildings is the single most cost-effective measure they could ever introduce.
@enrgy_manifesto
