3D graphics card which supports OpenGL 2.1 and GLSL 1.3 or OpenGL ES 2.0.Linux/Unix Windows 7 and above macOS 10.15 and above.D/L/Nakota and Ojibwe skycultures withdrawn.Zotti gave a presentation about Virtual Archaeoastronomy with Stellarium (YouTube) for the Society for Cultural Astronomy in the American Southwest (SCAAS) on February 25th, 2023 Wolf gave a presentation about Stellarium 1.0 (YouTube) at the Siberian Astronomical Forum SibAstro 2022 on September 25th, 2022 Wolf gave a presentation about Stellarium - key changes in the last 5 years (YouTube) at the Siberian Astronomical Forum SibAstro 2021 on September 25th, 2021 Zotti gave a presentation about Stellarium (YouTube) for the China-VO (Virtual Observatory of the Chinese Academy of Sciences) on February 1st, 2021 Zotti gave an invited talk (YouTube) at the IAU Symposium 367 on December 9th, 2020 Zotti gave a talk about creating 3D sceneries (YouTube) at the TAG2016 Skyscapes session on December 20th, 2016 add your own deep sky objects, landscapes, constellation images, scripts.ability to add new solar system objects from online resources. plugin system adding artifical satellites, ocular simulation, telescope control and more.skinnable landscapes with spheric panorama projection.HTTP interface (web-based control, remote control API).graphical interface and extensive keyboard control.spheric mirror projection for your own low-cost dome.fisheye projection for planetarium domes.very realistic atmosphere, sunrise and sunset.images of nebulae (full Messier catalogue).constellations for 40+ different cultures.asterisms and illustrations of the constellations.extra catalogue with more than 1 million deep-sky objects.default catalogue of over 80,000 deep-sky objects.extra catalogues with more than 177 million stars.default catalogue of over 600,000 stars.Project typically supports claims of additionality.Buyer agrees to pay fixed price through supplier or directly to seller.Project must be in same load zone as buyer.Buyer receives and takes title to physical energy.If the market price is lower than the VPPA price, the buyer must make up the difference. Additionality is a complicated concept, but implies the buyer’s investment is credited with creating new, clean sources of energy, an important distinction on sustainability reports and within the ESG community. Physical PPAs can also support claims of additionality.Ī VPPA establishes a fixed price for the electricity produced by the project, typically called the “strike price.” If the wholesale market price, i.e., the price the local grid pays the project developer for the power, exceeds the strike price, the VPPA buyer is paid the difference. Second, a VPPA can often support claims of additionality. The buyer owns those RECs, which it retires to reduce its scope 2 emissions. First, a renewable energy VPPA produces RECs. So, what’s in it for the buyer? A few things. Instead, the electricity produced from the project flows directly into its local grid. No electricity flows to the buyer from the renewable energy project, whether the project is a solar power array or windfarm. Along with the green power delivered, the energy buyer in a renewable energy PPA receives renewable energy certificates (RECs) for each MWh of energy produced.Ī virtual power purchase agreement is a purely financial instrument. For instance, a PPA contract enables them to run at least part of their operations on green power at a fixed, set price, which is great both for the environment and hedge against long-term power prices. The PPA is a contract that schedules the delivery of electricity to the buyer directly from the renewable project and sets its price.Ĭompanies and organizations enter into renewable energy PPAs for different reasons. (Note that in this article we are specifically concerned with renewable energy projects). So what’s the difference between a physical PPA and a virtual PPA?Ī physical power purchase agreement is a contract that a typically large energy buyer enters into with a project developer. One way large commercial, industrial, and institutional energy buyers can quickly and effectively green their portfolios, reduce their carbon footprints, and move towards net-zero carbon emissions is by entering into either a physical power purchase agreement (PPA) or virtual power purchase agreement (VPPA) for clean energy.
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