Basilique goes green
While I’ve taken some time away from Second Life, I’ve spent a lot of that time doing a deep dive to educate myself about climate change. I now volunteer 20 hours/week for a non-profit organisation that raises climate change awareness and facilitates climate change education. I’ve been engaged in university coursework in climate change science since September. I’ve learned about the state of the science, the climate system, earth’s energy budget, the carbon cycle, climate models, and how our future climate will look and feel.
We don’t talk about climate change in Second Life because Second Life is a fantasy world where we, not our environment, control everything. With that said, Second Life can be a useful simulator to learn more about using alternative energy sources, like solar and wind power.
In my climate change science coursework, I’ve used climate models to see the effects of rising temperatures on glaciers, I’ve learned about amplifying and stabilising feedback loops, and how human perturbations can impact the carbon cycle with expected (but devastating) responses.
What’s the bottom line? I’ve known climate change is a grave concern for many years. Now, I know that we’re urgently running out of time to mitigate and adapt to its crushing effects. We must decrease and eliminate our civilisation’s dependency on fossil fuels as an energy source as soon as possible if we want to save our civilisation and avoid the premature death of billions of people. This fact (combined with several other circumstances) has lead to an abrupt realignment of my priorities which doesn’t prioritise Second Life.
One of the well-known mitigations against climate change is alternative energy. As an exercise, I thought it would be an interesting thought experiment to see what it would take to make my region in Second Life, Basilique, to be 100% powered by renewable energy resources.
As many readers of this blog will know, Basilique is a small village set on Northern Italy’s Lago Garda. It consists of very few residential and commercial buildings, no motorised traffic and a tiny power infrastructure composed mainly of street and walkway electric lighting. The village has a population of 12 households (with a capacity for 30-40 people) but most of the residents are single.
Basilique is tiny. Still, because of its low complexity, Basilique is a useful site to model alternative energy mitigations to climate change.
What follows is a relatively detailed breakdown of how I made Basilique theoretically run on 100% renewable energy. If you want to skip my example and do this for yourself in RL or SL, follow these instructions.
First, find out how much electricity you need to live the average lifestyle of your region (e.g. Italy). That’s pretty easy to find out through the World Bank Data site. Just scroll down to your country and you’ll see how much energy people in your country use per capita. The figure is expressed in kWh – which means kilowatt hours (e.g. 5,159 kWh). Multiply that number by residents for which you want to supply power.
Second, you should identify how much 1 kWh costs in US dollars. While not exhaustive, the OVO energy site offers a handy list of several countries and their electricity prices in US dollars. Multiply that amount by your total power needs (step 1).
Third, go to the PVWatts Solar Energy Calculator and enter the variables starting with your location (you can use your RL address if you want to do this to get an idea of how much power solar panels could generate for you). It will select all the weather and solar radiation data for you, according to the nearest weather measurement station. Then follow the arrows. The trickiest part in the second page is DC System Size. It’s actually easy to figure out if you use their map tool to “draw your own system”. That will bring you to a map with a satellite image. Simply click the corners of your house and get the total area of your panel array. Record that total area in m2, you’ll need it later. For SL, you may have to do this with a corollary location to your region. Drawing the map is smart; because it will work out the System Capacity for you based on the area of your intended array. Look at the other options on the calculator and fill in what you can (especially the average cost of electricity, if you want to get the value of your power output to compare against your costs (see step 2). Then click the next arrow which will give you your possible kWh per year output.
Fourth, with the total meters you identified in the previous step, go and get your solar panels on the marketplace and install them with the planned tilt and azimuth. That’s it really, you’ve completed the simulation. If your output equals or exceeds your consumption (identified in step 1), you’re 100% renewable!
The Basilique Example
First, I decided to figure out how much energy the residents of the village would hypothetically use. I’m not talking about computing power to access Second Life. For this exercise, I chose to treat Basilique as if it were a physical location.
People in Italy use 5,159 kilowatt hours (per capita, 2014). This figure does not relate to the consumption of end-users (e.g. to cook or shower, etc.) but all energy needed as input to produce fuel and electricity for end-users (including infrastructure). This figure includes everything. Since there are roughly 12 residents of Basilique (who are not full-time residents by any stretch), the energy needed as input is 61,908 kWh per annum. To purchase this power would cost $17,334.24 (in Italy, where electricity cost averages $0.28/kWH). There are also tourists that visit from time to time and a more accurate model might include them, but I think we’re safe.
Because Basilique did not produce its power, all of its residents and visitor energy needs would need to come from the wider power grid. To offset this, we need to install local energy sources, like solar and wind power.
How much solar power would it take to power Basilique?
At first, I installed Photovoltaic (PV) solar panels on every flat or south facing roof. I found these mesh solar panels on the SL Marketplace for L$99. Fortunately, Basilique has a large amount of roof space available, and a lot of these roofs face south. In total, I managed to install 794 m2 of solar panels, or 1% of the land area of a full 65,536 m2 region.
Basilique is a rustic sim, and part of my aim included reducing the visual impacts of my mitigation efforts. The solar panel arrays are visible from some high vantage points but aren’t easy to see from the ground level.
In total, the installed solar panels would produce 145,565 kWh per annum of AC system output according to the PVWatts Solar Energy Calculator, which is considerably more than the power the residents would likely use (61,908 kWh per annum).
How to calculate solar panel requirements
First, everything depends on the weather and sunlight you can expect at your location. Basilique is an island in Lake Garda, with the nearest (TMY2) weather file at Verona-Villafranca, Italy, 45.38N and 10.87E. Location matters because solar radiation differs dramatically based on longitude and latitude and by month.
Second, I used the calculator to model AC system output. AC system output is the total power (kWh per year) produced by the energy source. AC system output depends on:
- The size of your solar panel array (or DC system size, which is the power rating of the photovoltaic array in kilowatts which depends on the array area (measured in m2 by 1 kW/m2 by module efficiency). I had several different solar panel arrays that ranged from 28 m2 to 80 m2. They totalled 794 m2
- The efficiency of the solar panels. I chose to model Premium (crystalline silicon) PV panels that have an approximate efficiency of 19%. Go big or go home, right?
- The array type: I would have chosen an axis tracking PV array (these are solar panels that follow the sun as it crosses the sky), but couldn’t find any on the SL marketplace, so I chose a PV array facing south at a fixed tilt.
- The system losses. Every solar panel system will have performance losses due to soiling, shading, wiring, connections, light-induced degradation, and age. The calculator estimated my system losses to be 14.08.
- The tilt (degrees) of the solar panels. Solar panels need to face south to work best (assuming you’re in the northern hemisphere, which Basilique is). The tilt of my solar panels is ~30 degrees because most of my roof pitches are 30 degrees.
- The Azimuth (degrees) of the solar panels. Azimuth is the angle clockwise from true north describing the direction the array faces. At Basilique, I made every array face south, which is 180 degrees.
Third, I found the average cost of electricity purchased from utilities in the area ($/kWh) so that I could understand the economics of the outputs from the solar panels. Knowing the average cost allows me to understand how much money Basilique would save by not using grid power. Knowing the average cost of electricity also enables me to understand how much surplus power I could theoretically sell back. The average cost of electricity purchased from utilities in Italy is $0.28 USD.
These are the inputs, and they would generate a total AC system output of 145,565 kWh per annum.
To understand the economic aspects of the model, I have to consider how much the solar panels would cost to purchase in RL. Based on pricing models available in the UK (I couldn’t find any for Italy), I estimated the cost of the solar panels would be $172,000 USD. That sounds like a lot, but don’t forget I’m trying to power a whole village here, not just one house (which would average $9000 USD).
The good news is that my panels generate $40,758.19 of power per annum (or what I’d pay for that power if I were buying it off the grid). Even better, my energy costs to provide for 12 residents would be $17,334.24, leaving me a tidy profit, after I pay back my investment in the solar panels, of course.
I did the math on that too, and modelled a payback in the 5th year, after which the panels would have paid for themselves with the energy costs I saved.
Since the power I generate exceeds the power Basilique needs by a factor of nearly 2, I could reduce the solar panels I modelled by almost 1/2, which would reduce my investment to $86,000 USD and my payback window to 2 years.
How much wind power would it take to power Basilique?
I underestimated the power I could produce from my solar panels and overestimated the amounts my residents would need, so I also installed half a dozen 12-metre wind turbines. It turns out I would only need three turbines that size.
Each turbine would theoretically produce 22,317 kWh per annum assuming the wind averaged 5.13m/s (modelled on the Evoco Energy Limited 10 (10 kW) 12 m tower which is as similar as I could find to the turbine I purchased on the SL Marketplace for L$98). I checked the SL mainland wind speed used by sailors, and it averages at ~4m/s; so, that’s close. The power that one turbine would produce is one-third of what I need to supply Basilique every year, and each turbine of that size costs around $50,000 USD to purchase in RL. With an annual income of $18,746, I’d pay back the three turbines in 9 years.
A slight problem with this exercise is population density. At first, I considered the theoretical need to power households in Second Life. Obviously, people in Second Life don’t live in homes there like they do in real life. Most SL residents don’t live in households. If anything, one person typically occupies one dwelling. Still, the population density of Italy is about 200 residents per square kilometre. At that density, Basilique (which is 0.065 km2) would have a population of 13 people – so, that’s about right. With that said, the average family household in Italy is 2.44 people per household. Powering the needs of 30 to 40 people exceeds what I’ve modelled by a factor of just under 2.5. For that average household size, I’d need 2.5 times more power generated (2.5 times more solar panels or 2.5 more wind turbines) that I found I required for this example.
Since I overestimated my power needs by double in both the solar and wind power cases, I’ll leave the set up as it is. Besides, it’s all about planning for the future, isn’t it?
If you’re interested in the work behind this model, see this spreadsheet.