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Solar PV Guide: Prices, Design, Installation & Pay-off Period
(ROI)
Solar Photo-voltaic (PV) technology is the way of
the future, for generating and supplying electric power for homes and businesses in the US and across the world. Despite the great potential of Solar PV, current cost and efficiency of solar panels makes them a green, yet expensive alternative to conventional ways of generating electricity, such as Coal, Gas and Oil fired power plants as well as Nuclear and Hydro electricity.
Main obstacle that is holding the wide-spread of solar PV is the long ROI (return on investment) that in some situations may exceed 10 years. Fortunately, US federal government and local and state governments have a multitude of incentives and rebate programs for solar and other renewable energy projects.
Planning a Solar PV system
When considering installing a Solar PV system, you as home or business owner will need a to know the future size of your solar system in kW ( 1 kilo watt is 1000 watts) and the cost associated with this solar system. You also need to establish your current annual electricity usage and decide if you want to reduce or completely eliminate the use of electricity that you purchase from your utility company.
First, gather your electric bills for the last 12 months, record your total electricity consumption – the number of kW-hours, and your the total amount you had to pay, excluding any late fees and other miscellaneous fees. Divide your total cost by the total number of kWh – this will give you real cost per kWh.
In Massachusetts, average cost of electricity for residential use is 19-24 cents per
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kWh, and 15-17 cents per kWh for commercial use. Both are set to increase by 20% in near future, as announced in April 2008, by local utility companies.
Designing a Solar PV system, tailored for your need
In Massachusetts and surrounding states, we have an average of 4.5 sun hours per day annually. This accounts for rainy and cloudy days as well as long, sunny summer days and short winter days.
To make best use of your solar system, you will need to capture as much sun-light as possible, therefore the best location to place your solar system is on the south-facing side of the roof. You also want them to be installed at a certain angle – about 20-30 degrees. Assuming the 4.5 hours of sun per day, a 1 kW Solar PV system will produce 4.5 kWh per day, and 135 kWh in a 30-day month (4.5 x 30 days). Please keep in mind that the energy produced is in DC volts, and when it goes through the conversion into AC, you lose about 20-25% of that electricity.
Average household electric consumption is 750 kWh per month for a single family home. To cover 100% of this consumption with solar electricity, you will need about 8 kW solar PV system. 135 kWh DC x 8 = 1080 kWh – 25% =810 kWh AC at 100% production output of solar panel. Note that ALL solar panels loose an average of 0.5% of production output per year, or 10 % through its 20-year warranty period.
Average residential solar installation is 2-4 kW system which usually eliminates 50-70% of electric power that you purchase. How ever those installations are still dependent on additional electricity.
Commercial solar installations can range from 10 kW to over 1 MW (1 megawatt = 1000 kW). Commercial Solar PV systems can supply power to the building they are installed on or they may be a so called solar farm – or a solar power plant supplying electric power directly into electric grid. For purpose of this guide, we will
concentrate on smaller, roof-top solar installations for individual home or business use, as solar farms topic goes way beyond the scope of this guide, and is considered a power utility for taxes and other purposes.
Solar PV Cost
National average cost to install a Solar PV system ranges from $9 to $12 per watt or $9000-12000 per kW DC (direct current) of solar system installed, with smaller installations being at the top for this price range due to fixed costs such as equipment, setup, installation, permits and paperwork.
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Most expensive component of the solar PV system are the solar panels themselves, however equipment such as inverter (which converts DC into AC and feeds it into your meter) also add considerable amount to a smaller size PV systems. Therefore for a 3 kW residential solar system, the cost will be around $11 per watt or $33000 total system cost when using conventional solar panels
Fortunately the $33000 price tag is not you actual cost, as many states have a wide range of rebates for solar PV installations as well as federal tax credits, available for both commercial and residential systems.
ROI and pay-off period for Solar PV
For purposes of this guide we will use two hypothetical solar PV systems – one being a 4 kW residential system and the other being a 25 kW commercial system. To simplify this guide and to avoid any confusion both of those systems are installed in Massachusetts. This way we know exactly what the MA state rebates are for each system and what the local electricity costs are from N-Star and National Grid utility companies. These two utility companies have the widest presence in MA market.
太阳能光伏指南：价格，设计，安装及收费期率（ ROI ）
太阳能光voltaic （光伏）技术是未来的方向，创造和提供电力的家庭和企业在美国和世界各地。尽管潜力巨大太阳能光电，目前的成本和效率的太阳能电池板使他们的绿色，但昂贵的替代传统的发电方式，如煤，天然气和石油发电厂以及核能和水电发电。
主要障碍是持有广泛的太阳能光伏是一项长期的投资回报率（投资回报） ，在某些情况下可能会超过10年。幸运的是，美国联邦政府以及地方和国家政府的多种奖励和退税计划的太阳能和其他可再生能源项目。
规划太阳能光伏系统
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在考虑安装太阳能光伏系统，您的家庭或企业所有者将需要知道未来的大小的太阳系千瓦（ 1公斤瓦是一〇 〇 〇瓦特）和与此相关的成本太阳系。您还需要确定您目前每年用电量，并决定是否要减少或完全消除用电您购买从您的公用事业公司。
首先，收集您的电费帐单为过去12个月中，记录您的总耗电量-人数千瓦小时，而您的总金额你不得不支付，但不包括任何滞纳金和其他杂项费用。将您的总费用的总数千瓦时-这将让您实际成本每千瓦时。
在马萨诸塞州，平均发电成本为住宅用途是19-24美分每千瓦小时，和15-17美分每千瓦时用于商业用途。两者都将增加20 ％ ，在不久的将来宣布，在2008年4月，由当地公用事业公司。
设计了太阳能光伏系统，专为您的需要
在马萨诸塞州和周边国家，我们有平均4.5小时，每一天太阳每年。这占雨季和阴天以及长，阳光充足的夏季和冬季天短。
最有效地利用您的太阳能系统，您将需要捕捉了阳光的可能，因此，最好的位置，将您的太阳系是在南南合作方面所面临的屋顶。你还希望他们能够被安装在某个角度-约20-30度。假设4.5小时的太阳每一天，一个1千瓦的太阳能光伏系统将产生4.5千瓦小时，每天和135千瓦时的30天的一个月（ 4.5 x 30天） 。请记住，产生的能量是直流电压，当它经过转换成交流电，你损失约20-25 ％的电力。
平均家电消费为750千瓦时，每月一个家庭。以支付100 ％的消费与太阳能发
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