Pros and a few cons of solar generation in Lorne

In the zero-emissions version of Lorne dreamed up by some of us, no trees were felled and no additional concrete was poured. The solar component of our renewable energy came entirely from existing roofs. Lorne uses a lot of electricity on hot days in summer when, fortuitously, the sun shines. In the worst weeks of winter, when there is another peak of consumption, we hoped the energy generated on the roofs of unoccupied houses would make up most of the shortfall. Thanks to a community agreement and a sophisticated grid, those of us with shaded roofs would contribute financially to panels on unshaded roofs and received a benefit. Total power outages would be a thing of the past, because the system and its storage would keep the lights on in Lorne. Visitors would recharge their electric vehicles at rapid recharge points drawing on renewable energy.

Disillusionment came as we met the people who actually knew about renewable energy and practicalities – Matt Armstrong of Southern Otway Sustainable (SOS) in Apollo Bay, Lachlan McClean (then at Surf Coast Shire Council), Daniel Brooke (Mondo Energy) and Patrick Turnbull (Western District Health). The reality is that there is no working model of the sort of thing we had in mind. The grid is one of the major hurdles.

But all was not lost. We made good contacts, and heard some good news stories, one of which is the Lorne hospital’s solar system which we wrote about in a previous newsletter. More is in the pipeline now that the Victorian government has released its climate change strategy. In Lorne this means that the government precinct (school, SES and police), which is well-suited to solar generation, should be 100% powered by renewable electricity by 2025. AND as icing on the cake Steve Bayley, convinced that solar would “work well for us because we mostly use power during the day when generation is high”, installed an 8 Kw solar system on the Tree Watch site in the industrial area.

Steve’s experience will mirror that of other people with solar installations and high demand for electricity during daylight hours.

Electricity generation and use on a spring day 2020 

On the day shown above, Tree Watch generated more electricity than it used. The excess was exported to the grid at $0.11 per kWh. At night electricity was imported at $0.27 per kWh. The net result, Steve says, is that “The Solar system cost Tree Watch $7000 and in the last six months the system has saved the company $700 in power bills, so the investment will hopefully pay itself off within 10 years.” Or in a much shorter time – Steve seems over pessimistic even allowing that it is winter. What’s more, Steve notes that “The electrical energy component of Tree Watch’s total energy consumption may now be close to carbon neutral.” Tree Watch is in the process of migrating some of its night-time use of electricity to the day to better match the solar generation curve and further reduce the payback period.

The Tree Watch system could be enlarged because there is spare roof space. “The financial benefits won’t be as dramatic as the first system but it will reduce our carbon footprint and potentially help the grid during the day” says Steve.

The ‘potential’ referred to goes beyond reducing the load on the grid during peak demand. Steve’s system is fitted with a smart widget called an UBI which not only tells Steve what is happening in real time, but could one day mean his panels become part of a community system called a ‘local microgrid’. Returning to our zero-emissions version of Lorne, we can imagine Steve’s electrons entering a pool that is drawn upon by Lorne users. Whenever supply exceeds demand the surplus would go to a neighbourhood battery for later use by the community. Only when the storage was full would left-over electrons depart Lorne on the main grid. This sort of system is a physical microgrid, and it’s the sort of system needed if the town is to be able to support itself during outages of the main grid.

Physical microgrids still seem a long way off, but virtual microgrids are a reality. These have some of the merits of physical ones but are accounting systems rather than physical ones. They can’t be ‘islanded’ from the main grid.

In any event, Tree Watch may soon have additional uses for electricity that will move it closer to carbon neutrality. Electrically powered heavy vehicles are on the horizon.

At Friends of Lorne we will continue to run thought experiments about locally-generated, renewable energy. We are well aware that there are downsides of solar generation too. One aspect, shading, is of particular concern for us. We have a long history of support for the natural environment including the tree canopy. Without that canopy we lose much of the diversity of creatures that we share Lorne with and which give Lorne its character. Those trees, by providing shade and evaporative cooling, also save us from becoming a heat island. We do not favour removing trees to increase electricity generation.